U.S. patent application number 12/092733 was filed with the patent office on 2008-11-27 for coatable compositions, coatings derived therefrom and microarrays having such coatings.
Invention is credited to Peter R. Johnson, John K. Simons, James T. Wolter.
Application Number | 20080294116 12/092733 |
Document ID | / |
Family ID | 56290872 |
Filed Date | 2008-11-27 |
United States Patent
Application |
20080294116 |
Kind Code |
A1 |
Wolter; James T. ; et
al. |
November 27, 2008 |
Coatable Compositions, Coatings Derived Therefrom and Microarrays
Having Such Coatings
Abstract
Coatable compositions and coatings derived from the coatable
compositions, and microarrays comprising such coatings are
described. In one aspect, the invention provides a microarray
comprising: a plurality of microneedles extending from a support
substrate; a coating deposited on at least one of the plurality of
microneedles, the coating comprising an active agent and a
biological salt. In another aspect, the invention provides a
coatable composition, comprising: active agent; a biological salt;
and solvent. In still another aspect, the invention provides a
dried coating coated on a microneedle, the coating comprising: an
active agent; and a biological salt.
Inventors: |
Wolter; James T.; (Oakdale,
MN) ; Simons; John K.; (Maplewood, MN) ;
Johnson; Peter R.; (Eagan, MN) |
Correspondence
Address: |
3M INNOVATIVE PROPERTIES COMPANY
PO BOX 33427
ST. PAUL
MN
55133-3427
US
|
Family ID: |
56290872 |
Appl. No.: |
12/092733 |
Filed: |
November 17, 2006 |
PCT Filed: |
November 17, 2006 |
PCT NO: |
PCT/US06/44553 |
371 Date: |
May 6, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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60753617 |
Dec 23, 2005 |
|
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60754786 |
Dec 29, 2005 |
|
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60747618 |
May 18, 2006 |
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Current U.S.
Class: |
604/173 ;
424/184.1 |
Current CPC
Class: |
A61M 2037/0023 20130101;
A61K 47/32 20130101; A61M 2037/0046 20130101; A61K 9/0021 20130101;
A61K 47/12 20130101; A61K 47/26 20130101; A61M 37/0015
20130101 |
Class at
Publication: |
604/173 ;
424/184.1 |
International
Class: |
A61M 5/32 20060101
A61M005/32; A61K 39/00 20060101 A61K039/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2005 |
US |
PCT/US2005/041858 |
Claims
1. A microarray comprising: A plurality of microneedles extending
from a support substrate; A coating deposited on at least one of
the plurality of microneedles, the coating comprising an active
agent and a biological salt.
2. A microarray according to claim 1 wherein the height of the
microneedles is between about 1 .mu.m and about 400 .mu.m.
3. A microarray according to claim 1 wherein the microneedles each
have an aspect ratio of at least about 2:1.
4. A microarray according to claim 1 wherein the microneedles each
have an aspect ratio of at least about 3:1.
5. A microarray according to claim 1 wherein the microneedles each
have an aspect ratio of at least about 5:1.
6. A microarray according to claim 1 wherein the microarray
comprises up to 1000 microneedles extending from a support
substrate.
7. A microarray according to claim 1 wherein each microneedle
comprises a base portion attached to the support substrate and a
tip portion distal from the support substrate, the coating being
deposited on the tip portion of at least one of the plurality of
microneedles.
8. A microarray according to claim 1 wherein the biological salt is
selected from a carboxylated organic salt, a hydroxylated organic
salt or a combination of the foregoing.
9. A microarray according to claim 1 wherein the biological salt is
a salt of citric acid.
10. A microarray according to claim 9 wherein the salt of citric
acid is selected from monosodium citrate, disodium citrate,
trisodium citrate, monopotassium citrate, monopotassium citrate,
monopotassium citrate, and combinations of two or more of the
foregoing.
11. A microarray according to claim 10 wherein the active agent is
an antigen adsorbed on an aluminum adjuvant.
12. A microarray according to claim 1 wherein the active agent is a
vaccine.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to International Patent
Application Serial No. US2005/041858, filed on Nov. 18, 2005, U.S.
Provisional Application Ser. Nos. 60/753,617, filed on Dec. 23,
2005, 60/754,786, filed on Dec. 29, 2005, 60/747,618, filed on May
18, 2006, all of which are incorporated herein by reference.
FIELD
[0002] The present invention relates to coatable compositions and
coatings derived from the coatable compositions, and to microarrays
comprising such coatings.
BACKGROUND
[0003] Some therapeutic molecules can be transported through the
skin. The principal barrier to the transport of molecules through
the skin is the stratum corneum (the outermost layer of the skin).
Devices or "microarrays" equipped with one or more microneedles
have been disclosed for use in the delivery of active agents and
other substances through the skin and other surfaces. In use, the
microarray is pressed against the skin with sufficient force to
cause the microneedles to puncture the stratum corneum and thereby
create a plurality of microscopic slits through which the
transdermal delivery of one or more active agents may be
accomplished. Similarly, fluid sampling may be facilitated by the
creation of such microscopic slits.
[0004] In delivering a therapeutic molecule or active agent through
the stratum corneum, a microarray can be associated with a fluid
reservoir that can temporarily retain a liquid formulation of
active agent prior to its delivery through mammalian skin. In some
constructions, the microneedles are hollow structures that provide
a path for liquid to flow directly from the fluid reservoir through
the microneedles and through the skin. In other constructions, an
active agent may be coated on the outer surfaces of a microarray so
that the active agent on the surfaces of the microneedles is
exposed to interstitial fluids as soon as the microneedles have
pierced through the stratum corneum. Once the microneedles are in
contact with interstitial fluid, the coating can dissolve. The goal
of such a configuration is to dissolve the active agent into the
interstitial fluid so that it can enter the body to perform its
therapeutic function.
[0005] However, active agents can have a strong affinity to the
microneedle materials, and such an affinity can interfere with the
disassociation of active agent from a microneedle surface. Although
the concentration of active agent(s) in a coating can be increased
to compensate for the inability to disassociate all of the active
agent from the microneedles, the amount of active agent left on the
microneedles of a used microarray is wasteful and can present
disposal issues.
SUMMARY
[0006] The present invention provides compositions comprising
active agents that can be transdermally delivered into a mammalian
body from dried coatings on the outer surfaces of the
microneedle(s) in a microarray. In one aspect, the invention
provides a microarray comprising:
[0007] A plurality of microneedles extending from a support
substrate;
[0008] A coating deposited on at least one of the plurality of
microneedles, the coating comprising an active agent and a
biological salt.
[0009] In another aspect, the invention provides a coatable
composition, comprising:
[0010] Active agent;
[0011] A biological salt; and
[0012] Solvent.
[0013] In still another aspect, the invention provides a dried
coating coated on a microneedle, the coating comprising:
[0014] An active agent; and
[0015] A biological salt.
[0016] Unless indicated herein to the contrary, words, terms or
phrases will be understood as having their ordinary meaning as
understood by those skilled in the art. The following definitions
are applicable to the present invention.
[0017] As used herein, the terms "a," "an," "the," "at least one,"
and "one or more" will be understood as being interchangeable. For
example, a formulation comprising "an effective amount of a
pharmaceutical agent" will be understood to mean that the
composition includes at least one active agent.
[0018] "Active agent" refers to one or more pharmacologically or
pharmaceutically effective molecules, compounds, materials or
substances producing one or more local or systemic effects in
mammals, including humans. Examples of active agents include,
without limitation, small molecules, polypeptides, proteins,
oligonucleotides, nucleic acids, polysaccharides, drugs, vaccines
or other immunologically active agents or an agent capable of
triggering the production of an immunologically active agent.
[0019] "Biological salt" refers to a salt that is biologically
compatible with the interstitial fluid in a mammalian body.
[0020] "Coatable composition" refers to liquid mixtures such as
solutions, emulsions, dispersions and the like that include at
least one active agent, solvent (e.g., water) and at least one
biological salt as components thereof.
[0021] "Effective amount," when referring to the amount of active
agent, refers to an amount that is sufficient to provide a local or
systemic therapeutic (e.g., physiological or pharmacological)
result. In a particular instance, the actual amount of active agent
that is needed to provide a desired therapeutic effect will depend
on a number of factors including the nature and identity of the
active agent, the severity of the condition being treated, the site
of delivery and the like.
[0022] "Microneedle" refers to one or more microscopic needle-like
structures associated with a microarray and capable of piercing the
stratum corneum to facilitate the transdermal delivery of
pharmaceutical agents or the sampling of fluids through the
skin.
[0023] "Microarray" refers to the medical devices described herein
that includes one or more microneedles capable of piercing the
stratum corneum to facilitate the transdermal delivery of
therapeutic agents or the sampling of fluids through the skin.
[0024] "Vaccine" refers to conventional and/or commercially
available vaccines including but not limited to the flu vaccine,
Lyme disease vaccine, rabies vaccine, measles vaccine, mumps
vaccine, chicken pox vaccine, small pox vaccine, hepatitis vaccine,
pertussis vaccine, rubella vaccine, diphtheria vaccine,
encephalitis vaccine, yellow fever vaccine, recombinant protein
vaccine, DNA vaccine, polio vaccine, therapeutic cancer vaccine,
herpes vaccine, pneumococcal vaccine, meningitis vaccine, whooping
cough vaccine, tetanus vaccine, typhoid fever vaccine, cholera
vaccine, and tuberculosis vaccine. The term "vaccine" thus
includes, without limitation, antigens in the forms of proteins,
polysaccarides, oligosaccarides, or weakened or killed viruses.
[0025] Those skilled in the art will more fully appreciate the
features of the invention upon consideration of the remainder of
the disclosure including the Detailed Description, taken together
with the various Figures, and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In the describing the embodiment(s) of the invention,
reference is made to the various Figures in which features of the
embodiments are indicated using reference numeral and wherein like
reference numerals indicate like structures, and wherein:
[0027] FIG. 1 is a perspective view of a patch having a microarray
and suitable for use in the present invention; and
[0028] FIG. 2 is a side elevation, in cross section, of a portion
of a microarray having a plurality of microneedles, the distal ends
of each microneedle coated with a composition comprising an active
agent, according to the invention.
DETAILED DESCRIPTION
[0029] The present invention provides for the delivery of active
agents through the stratum corneum. In general, the described
embodiments utilize coatable formulations comprising one or more
active agents that may be applied to (e.g., coated on) one or more
microneedles of a microarray. Once the coated formulation has dried
on the microneedle(s), the microarray may be pressed against the
skin of a mammal to create at least one slit and typically a
plurality of slits in the stratum corneum where the dried coating
will dissolve in interstitial fluids to thereby deliver the active
agent.
[0030] Referring to the various Figures, embodiments of the
invention are shown and will now be described. FIG. 1 illustrates a
transdermal patch 20 in the form of a combination of a microarray
22, pressure sensitive adhesive 24 and backing 26. The microarray
22 includes a plurality of microneedles 10 protruding from a
substrate surface 14. The microneedles 10 may be arranged in any
desired regular or irregular pattern or they may be distributed
over the substrate surface 14 randomly. The microneedles 10 are
arranged in uniformly spaced rows. However, some embodiments of the
invention can comprise non-uniform distributions of the
microneedles, and the invention is not limited to any particular
distribution or arrangement of the microneedles in the microarray.
The microarray may optionally contain additional
non-microstructured features, such as flanges, connectors, etc. A
microarray can include a mixture of microneedles having, for
example, various heights, diameters, cross-sectional shapes, and
spacings between the microneedles.
[0031] In some embodiments, the height of the microneedles 10
(e.g., the distance form the substrate surface 14 and the distal
end or tip of the microneedle) is between about 1 .mu.m to about
400 .mu.m. In some embodiments, the height of the microneedles is
between about 50 .mu.m and about 400 .mu.m. In still other
embodiments, the microneedles can have a height of between about
100 and about 400 .mu.m. The height of the microneedle may be
selected to accommodate the site on the mammalian body chosen for
delivery of the active agent, namely, the stratum corneum.
[0032] Microneedles suitable for use in embodiments of the
invention can be characterized as having needle or needle-like
structures, or as comprising small blades or pin-like projections,
all of which are capable of piercing the stratum corneum. In some
embodiments, microneedles may be characterized by their aspect
ratio (e.g., the ratio of the height of the microneedle to its
maximum base dimension). In some embodiments of the present
invention, useful microneedles can have an aspect ratio of at least
about 2:1. In some embodiments, the aspect ratio may be at least
about 3:1, and in still other embodiments, the aspect ratio may be
at least about 5:1.
[0033] Microneedles useful in the present invention may have any of
a variety of configurations. The microneedles in a single
microarray may all be of the same configuration or they may
comprise more than one configuration. In some embodiments of the
invention, pyramidal microneedles can be used in which the
microneedle has a rectangular base so that the maximum base
dimension is a diagonal line connecting opposed corners across the
base. In some embodiments, the microneedles may be solid, flat or
may have a circular or polygonal cross section. In some
embodiments, the microneedles can have straight shafts or tapered
shafts and may be circular, or of some other shape (e.g.,
polygonal), in cross section. Microneedles suitable for use in some
embodiments of the invention may have a curved blade-like
configuration or they might be provided with a v-section or groove.
Microneedles having other more complex shapes are also useful
within the scope of the present invention to, for example, enhance
adherence and fluid dynamics.
[0034] In some embodiments, useful microneedles can comprise
structures like those disclosed in U.S. Pat. No. 6,881,203 B2
(Delmore et al.), issued Apr. 19, 2005. The microneedles of the
'203 patent are tapered and each microneedle includes at least one
channel in its outer surface. The microneedles may each have a base
that is elongated in one direction, and the channel may extend from
one of the ends of the elongated base to the tip of the
microneedle. The channels formed along the sides of the
microneedles may terminate prior to reaching the tips. Conduit
structures may be provided on the surface of the base on which the
microneedles are located, and the channels in the microneedles may
be in fluid communication with the conduit structures. In other
embodiments, the microneedles can comprise structures like those
disclosed in co-pending U.S. patent application Ser. No. 10/621,620
filed on Jul. 17, 2003 (Atty. Ref. 57901US005) entitled
"Microneedle Devices and Microneedle Delivery Apparatus" which
describes microneedles having a truncated tapered shape and a
controlled aspect ratio.
[0035] The microneedle array for use in the present invention may
comprise a plurality of microneedles. In some embodiments, there
may be up to 1000 microneedles per device. In other embodiments,
there may be to 500 microneedles per device. Other embodiments are
also contemplated.
[0036] In embodiments of the invention, the microneedles 10 of the
microarray have a patient-facing surface area of more than about
0.1 cm.sup.2 and typically less than about 20 cm.sup.2. In some
embodiments, microneedles 10 of the microarray can have a
patient-facing surface area of more than about 0.5 cm.sup.2 and
less than about 5 cm.sup.2. In another embodiment, the surface of
the microneedles 10 can comprise an area of more than about 1
percent and less than about 75 percent of the total area of the
microarray surface that faces a skin surface of a patient (e.g.,
the combined surface area of the microneedles 10 and the substrate
surface 14). In other embodiments, the surface of the microneedles
10 has an area of more than about 0.10 square inch (0.65 cm.sup.2)
and less than about 1 square inch (6.5 cm.sup.2).
[0037] A coatable composition is used to coat the microneedles 10.
The coatable composition is prepared by mixing a solvent, one or
more active agents and at least one biological salt. Solvent
suitable for a coatable composition can be selected from any of a
variety of liquids. In embodiments of the invention, the solvent is
a polar molecule that can be readily evaporated at ambient
temperatures or at moderately elevated temperatures. In some
embodiments, suitable solvents may be selected from liquids such as
water, dimethyl sulfoxide, dimethyl formamide, ethanol, isopropyl
alcohol, and mixtures of two or more of the foregoing.
[0038] In embodiments of the invention, the coatable composition is
coated onto the microneedles of a microarray according to any of a
variety of coating methods so that, when dried, a coating
comprising active agent and biological salt remains on the distal
portions (e.g., the tips) of the microneedles within the
microarray. In some embodiments, the compositions are coated onto
the microneedles according to the technique described in co-pending
U.S. Provisional Patent Application Ser. No. 60/629,209, filed on
Nov. 15, 2004 (Attorney Ref. 60350US002), the entire disclosure of
which is incorporated herein by reference thereto.
[0039] Coatable compositions useful in the invention comprise at
least one biological salt. The biological salt may be, for example,
an organic salt normally present in a mammalian body as a component
of interstitial fluid, for example. Biological salts are selected
for inclusion in the coatable compositions to be resistant to
evaporation so as to become part of a dried coating that also
comprises active agent. Biological salt will facilitate a
relatively rapid rate of release of active agent from the dried
coating. In embodiments of the invention, the rate of release of
active agent in the presence of a biological salt is greater than
would typically be observed for the same active agent in a coating
that includes no biological salt.
[0040] In embodiments of the invention, a dried coating is formed
from the coatable composition on the microneedles of a microarray.
The coating comprises biological salt and active agent, and the
biological salt is selected to enhance or facilitate the
displacement of active agent(s) (e.g., antigens) from a substrate
(e.g., a microneedle) and/or from other substances such as, for
example, an adjuvant (e.g., aluminum adjuvant associated with a
vaccine). Biological salt in a dried coating facilitates the rapid
release of active agent into interstitial fluid, and the biological
salt is chosen to have an affinity with the active agent greater
than the affinity of the active agent for the microneedles or the
materials from which the microneedles are made.
[0041] In some embodiments, the biological salt is an organic salt
that is a carboxylated salt. In some embodiments, the biological
salt is an organic salt that is a hydroxylated salt. In some
embodiments, the salt is a naturally occurring component of
mammalian interstitial fluid. In still other embodiments, the
biological salt is not naturally occurring in mammalian
interstitial fluid. Those skilled in the art will appreciate that
the selection of a biological salt for inclusion in a particular
coatable composition will be influenced by any of several factors
such as the nature of the active agent, the material used in the
microneedles of a microarray onto which a composition will be
applied, the affinity of the active agent for the microprotrusion
material, the affinity of the active agent for a particular
biological salt, and the like.
[0042] In embodiments in which the active agent is an antigen
adsorbed on an aluminum adjuvant, the biological salt may comprise
one or more components normally found in interstitial fluid. In
some embodiments, salts of citric acid serve as biological salts to
bind a coated antigen, adjuvant, or antigen-adjuvant complex to a
micro-projection. The inclusion of citric acid salts in the
coatable compositions and the resulting dried coatings according to
the present invention can provide a more rapid and complete
dissolution and release of active agent (e.g., antigen and
adjuvant) into interstitial fluid while also enhancing the coating
properties of certain compositions (e.g., vaccine formulations). In
aspect of the foregoing embodiment, biological salt(s) can comprise
sodium and/or potassium salts of citric acid such as monosodium
citrate, disodium citrate, trisodium citrate, monopotassium
citrate, dipotassium citrate, tripotassium citrate and combinations
of two or more of the foregoing.
[0043] One or more active agents are included in the coatable
compositions and the dried coatings of the invention in amounts
sufficient to deliver an effective amount of the active agent to a
mammalian patient so that a desired therapeutic result can be
achieved. In practice, the amount of the active agent in the
coatings can vary widely depending upon the specific active agent,
the site of delivery, the severity of the condition being treated,
the desired therapeutic effect and the dissolution and release
kinetics for delivery of the agent from the coating into skin
tissues. In some embodiments, the coatable composition includes 100
parts by weight of at least one active agent, and at least 50 parts
by weight of at least one biological salt.
[0044] In some embodiments, the active agent is a vaccine. In some
embodiments of the invention, more than one active agent may be
incorporated into the coating composition. In compositions
incorporating a vaccine, the vaccine typically includes an antigen
or antigenic composition capable of eliciting an immune response
against a human pathogen, which antigen or antigenic composition is
derived from a virus or an infectious agent that can cause disease
or symptoms that can be treated with microneedle arrays of the
present invention. Examples of viruses, include, but are not
limited to the following DNA and RNA viruses and viral families:
Arbovirus, Adenoviridae, Arenaviridae, Arterivirus, Birnaviridae,
Bunyaviridae, Caliciviridae, Circoviridae, Coronaviridae, Dengue,
EBV, HIV, Flaviviridae, Hepadnaviridae (Hepatitis), Herpesviridae
(such as, Cytomegalovirus, Herpes Simplex, Herpes Zoster),
Mononegavirus (e.g., Paramyxoviridae, Morbillivirus,
Rhabdoviridae), Orthomyxoviridae (e.g., Influenza A, Influenza B,
and parainfluenza), Papiloma virus, Papovaviridae, Parvoviridae,
Picornaviridae, Poxviridae (such as Smallpox or Vaccinia),
Reoviridae (e.g., Rotavirus), Retroviridae (HTLV-I, HTLV-II,
Lentivirus), B. pertussis (for example pertactin, pertussis toxin
or derivatives thereof, filamenteous hemagglutinin, adenylate
cyclase, fimbriae), B. parapertussis and B. bronchiseptica and
Togaviridae (e.g., Rubivirus). Viruses falling within these
families can cause a variety of diseases or symptoms, including,
but not limited to: arthritis, bronchiollitis, respiratory
syncytial virus, encephalitis, eye infections (e.g.,
conjunctivitis, keratitis), chronic fatigue syndrome, hepatitis (A,
B, C, E, Chronic Active, Delta), Japanese B encephalitis, Junin,
Chikungunya, Rift Valley fever, yellow fever, meningitis,
opportunistic infections (e.g., AIDS), pneumonia, Burkitt's
Lymphoma, chickenpox, hemorrhagic fever, Measles, Mumps,
Parainfluenza, Rabies, the common cold, Polio, leukemia, Rubella,
sexually transmitted diseases, skin diseases (e.g., Kaposi's,
warts), purified or recombinant proteins thereof and viremia,
polynucleotides or polypeptides, or agonists or antagonists of the
invention, can be used to treat or detect any of these symptoms or
diseases. In specific embodiments, microneedle arrays are used to
treat: meningitis, Dengue, EBV, and/or hepatitis (e.g., hepatitis
B). In an additional specific embodiment, polynucleotides,
polypeptides, or agonists or antagonists of the invention are used
to treat patients non-responsive to one or more other commercially
available hepatitis vaccines. In a further specific embodiment,
microneedles of the invention are used to treat AIDS.
[0045] Similarly, bacterial and fungal agents that can cause
disease or symptoms and that can be treated with microneedle arrays
of the present invention include, but not limited to, the following
Gram-Negative and Gram-positive bacteria, bacterial families, and
fungi: Actinomyces (e.g., Norcardia), Acinetobacter, Cryptococcus
neoformans, Aspergillus, Bacillaceae (e.g., Bacillus anthrasis),
Bacteroides (e.g., Bacteroides fragilis), Blastomycosis,
Bordetella, Borrelia (e.g., Borrelia burgdorferi), Brucella,
Candidia, Campylobacter, Chlamydia, Clostridium (e.g., Clostridium
botulinum, Clostridium dificile, Clostridium perfringens,
Clostridium tetani), Coccidioides, Corynebacterium (e.g.,
Corynebacterium diptheriae), Cryptococcus, Dennatocycoses, E. coli
(e.g., Enterotoxigenic E. coli and Enterohemorrhagic E. coli),
Enterobacter (e.g. Enterobacter aerogenes), Enterobacteriaceae
(Klebsiella, Salmonella (e.g., Salmonella typhi, Salmonella
enteritidis, Salmonella typhi), Serratia, Yersinia, Shigella),
Erysipelothrix, Haemophilus (e.g., Haemophilus influenza type B),
Helicobacter, Legionella (e.g., Legionella pneumophila),
Leptospira, Listeria (e.g., Listeria monocytogenes), Mycoplasma,
Mycobacterium (e.g., Mycobacterium leprae and Mycobacterium
tuberculosis), Vibrio (e.g., Vibrio cholerae), Neisseriaceae (e.g.,
Neisseria gonorrhea, Neisseria meningitidis), Pasteurellacea,
Proteus, Pseudomonas (e.g., Pseudomonas aeruginosa),
Rickettsiaceae, Spirochetes (e.g., Treponema spp., Leptospira spp.,
Borrelia spp.), Shigella spp., Staphylococcus (e.g., Staphylococcus
aureus), Meningiococcus, Pneumococcus and Streptococcus (e.g.,
Streptococcus pneumoniae and Groups A, B, and C Streptococci), and
Ureaplasmas.
[0046] The foregoing bacterial, parasitic, and fungal families can
cause diseases or symptoms, including, but not limited to:
antibiotic-resistant infections, bacteremia, endocarditis,
septicemia, eye infections (e.g., conjunctivitis), uveitis,
tuberculosis, gingivitis, bacterial diarrhea, opportunistic
infections (e.g., AIDS related infections), paronychia,
prosthesis-related infections, dental caries, Reiter's Disease,
respiratory tract infections, such as Whooping Cough or Emphysema,
sepsis, Lyme Disease, Cat-Scratch Disease, dysentery, paratyphoid
fever, food poisoning, Legionella disease, chronic and acute
inflammation, erythema, yeast infections, typhoid, pneumonia,
gonorrhea, meningitis (e.g., meningitis types A and B), chlamydia,
syphilis, diphtheria, leprosy, brucellosis, peptic ulcers, anthrax,
spontaneous abortions, birth defects, pneumonia, lung infections,
ear infections, deafness, blindness, lethargy, malaise, vomiting,
chronic diarrhea, Crohn's disease, colitis, vaginosis, sterility,
pelvic inflammatory diseases, candidiasis, paratuberculosis,
tuberculosis, lupus, botulism, gangrene, tetanus, impetigo,
Rheumatic Fever, Scarlet Fever, sexually transmitted diseases, skin
diseases (e.g., cellulitis, dermatocycoses), toxemia, urinary tract
infections, wound infections, noscomial infections.
[0047] Moreover, parasitic agents causing disease or symptoms that
can be treated or prevented with microneedle arrays of the present
invention include, but not limited to, the following families or
class: Amebiasis, Babesiosis, Coccidiosis, Cryptosporidiosis,
Dientamoebiasis, Dourine, Ectoparasitic, Giardias, Helminthiasis,
Leishmaniasis, Schistisoma, Theileriasis, Toxoplasmosis,
Trypanosomiasis, and Trichomonas and Sporozoans (e.g., Plasmodium
virax, Plasmodium falciparium, Plasmodium malariae and Plasmodium
ovale). These parasites can cause a variety of diseases or
symptoms, including, but not limited to: Scabies, Trombiculiasis,
eye infections, intestinal disease (e.g., dysentery, giardiasis),
liver disease, lung disease, opportunistic infections (e.g., AIDS
related), malaria, pregnancy complications, and toxoplasmosis.
[0048] Coatable compositions according to the present invention may
include an adjuvant, although a single molecule may contain both
adjuvant and antigen properties (e.g., cholera toxin). Adjuvants
useful in the present invention include those known in the
art--i.e., see, Vaccine Design--The Subunit and Adjuvant Approach,
1995, Pharmaceutical Biotechnology, Volume 6, Eds. Powell, M. F.,
and Newman, M. J., Plenum Press, New York and London, ISBN
0-306-44867-X. Adjuvants are substances used to specifically or
non-specifically potentiate an antigen-specific immune response. In
some embodiments, the adjuvant and the composition are mixed prior
to presentation of the antigen, In other embodiments, the adjuvant
and the antigen may be separately presented within a short interval
of time.
[0049] Adjuvants should be capable of augmenting, enhancing,
directing, or otherwise improving an immune response. Suitable
adjuvants for use with the present invention include: aluminum or
calcium salts (hydroxide or phosphate); aluminum phosphate gel; oil
in water emulsions; particulate carriers such as liposomes;
immunologically active saponin fractions (e.g. Quil A) having
adjuvant activity derived from the bark of the South American tree
Quillaja Saponaria Molina; derivatives of Quil A, for example QS21
(an HPLC purified fraction derivative of Quil A); algal glucan,
.beta.-glucan; cholera toxin B subunit, heat-shock proteins (HSPs);
gamma inulin, GMDP (N-acetylglucosamine
.beta.1-4)-N-acetylmuramyl-L-alanyl-D-glutamine); GTP-GDP;
Imiquimod; ImmTher.RTM. (DTP-GDP); Loxoribine, MPL.RTM.; MTP-PE;
Murametide; Pleuran (.beta.-glucan); Murapalmitine; S-28463
(4-Amino-.alpha.,.alpha.-dimethyl-1H-imidazo[4,5-c]quinoline-1-ethanol);
Scalvo Peptide (IL-1.beta.; 163-171 peptide); Theramide.RTM.; amd
bacterial lipopolysaccharides such as 3D-MPL (3-O-deacylated
monophosphoryl lipid A). In some embodiments, suitable adjuvants
include aluminum salts, such as alum which is potassium aluminum
sulfate dodecahydrate (KAl(SO.sub.4).sub.2.12H.sub.2O) and
hydrolysis and hydration products of alum, such as
Al[H.sub.2O].sub.6.sup.3+, Al(OH).sub.2.sup.+, AlO(OH) and
Al(OH).sub.3. Further description of suitable adjuvants may be
found in U.S. Pat. Nos. 5,057,540 (Kensil et al.), 6,146,632 (Momin
et al.), and 6,299,884 (Van Nest et al.) and U.S. Patent
Application Publication No. 2001/053365 (Friede et al.), the entire
disclosures of which are incorporated herein by reference.
Combinations of two or more of the foregoing are also
contemplated.
[0050] The coatable compositions may also contain additional
excipients such as viscosity modifiers, stabilizers, surfactants,
pH modifiers, and other additives. Suitable additional excipients
include sucrose, ovalbumin, and hydroxyethyl cellulose.
[0051] In preparing one or more microarrays, a coatable composition
is applied to the microneedles using any of a variety of coating
methods. In some embodiments, the placement of coatable composition
is targeted for those portions of the microneedles that are most
likely to penetrate the skin, such as on the distal portions or
tips of the microneedles which comprise the distal half to distal
one third of a microneedle. For example, the coatable composition
can be coated onto the microneedles of a microarray by immersion,
spray coating and/or roll coating, dip-coating or the like. On
suitable roll coating method for use in the present invention is
that disclosed in U.S. patent application Ser. No. 10/099,604,
filed Mar. 15, 2002.
[0052] Following placement, the coatable composition is dried to
provide a coating comprising the active agent and biological salt.
Those skilled in the art will appreciate that the thickness of the
dried coating will be dependent on the density of the microneedles
on the microarray and the viscosity and concentration of the
coating composition as well as the coating method chosen. In some
embodiments, the coatable composition will be applied to a
microarray to achieve a dried coating thickness of less than about
100 microns. In some embodiment, the dried coating thickness is
less than 50 microns. In other embodiments, the dried coating
thickness is less than 10 microns. In still other embodiments, the
dried coating thickness is in the range of about 1 to about 10
microns.
[0053] Following the application of a coatable composition, it can
be dried to remove volatile components, such as solvents and the
like, to provide a dried coating comprising active agent and
biological salt. As used herein, the term "dried coating" refers to
a coating that is substantially free of volatile solvent, but the
dried coatings may retain some moisture, typically in equilibrium
with the atmosphere surrounding the microneedle array. In
embodiments of the invention, the composition is dried at ambient
temperature, with or without a forced air current. In other
embodiments, the coatable composition is dried by the application
of heat in an oven or the like. Alternatively, the coated
composition can be lyophilized, freeze dried, air dried, vacuum
dried or the like in order to remove solvent and other volatile
components and provide a dried coating. Drying or evaporation
conditions may be selected so as to avoid degradation of the active
agent and the biological salt in the dried coating.
[0054] Referring to FIG. 2, a portion of a microarray is
illustrated with a dried coating 140 comprising an active agent
disposed on the distal portion or tip of each microneedle 110. In
some embodiments, the distal portion of a microneedle can comprise
the distal-most one half portion of the surface area of a
microneedle. In other embodiments, the distal portion of a
microneedle can comprise the distal-most one third of the surface
of the microneedle. In still other embodiments, the distal portion
of a microneedle can comprise a portion of a microneedle's surface
area that is less than the distal-most one third thereof. The dried
coating 140 may be in the form of any of a variety of shapes such
as a thin laminar coating, like that shown in FIG. 2, disposed over
the distal portions or tips of the microneedles 110. In some
embodiments, the dried coating may be more rounded in its
configuration so that it resembles a droplet disposed on the tips
of the microneedles 110. The dried coating may be uniformly
configured across a microneedle so that the coating is symmetrical
and more or less adapts the same shape as that of the microneedle.
However, the shape of the dried coating may also vary so that it is
asymmetrical over any single microneedle or it may vary in
appearance and configuration from one microneedle to the next in a
microarray. It will also be appreciated that the dried coating may
at least partially extend to the lower portions of the microneedles
110 nearest the surface of support substrate 114. In some
embodiments, the dried coating may also be deposited on at last a
portion of the substrate 114.
[0055] Microarray devices may also be used for immediate delivery,
that is where they are applied and immediately removed from the
application site. They may also be left in place for an extended
time, which may range from a few minutes to as long as 1 week. It
will be appreciated that the microarray devices may be provided in
the form of a "patch" that can be adhered to the skin during the
time needed to deliver active agent through the stratum corneum. In
some embodiments of the invention, a microarray having a dried
coating as described herein may be applied to mammalian skin for an
extended time of delivery such as from about 1 to about 30 minutes
to allow for more complete vaccination than can be obtained upon
application and immediate removal. In another aspect, an extended
time of delivery may be as long as 1 hour, 1 day, or 1 week.
Preparative and Test Procedures
[0056] In the Examples that follow, certain procedures were
followed in the preparation of the Examples and in carrying out the
testing described herein.
Testing Procedure for Tetanus Toxoid Total-Array Content
[0057] A sample extraction solvent was prepared containing 50 mM
potassium perchlorate, 50 mM potassium citrate, 20 mM sodium
phosphate, 376 mM sodium chloride, and 100 .mu.g/mL bovine serum
albumin. A high performance liquid chromatography ("HPLC") sample
solution was prepared by placing an array into a polypropylene cup,
adding 1.0 mL of the sample extraction solvent to the cup, snapping
a cap onto the sample cup, and sonicating for 30 minutes.
[0058] Gradient elution HPLC (Mobile phase A): 0.2% (v/v)
perchloric acid; Mobile phase B: 10% water, 88% acetonitrile, 2%
isopropanol, 0.2% perchloric acid (70%); Solvent Program: 0.00 min,
22% B, 1.0 mL/min; 6.00 min, 58% B, 1.0 mL/min; 6.01 min, 100% B,
1.0 mL/min; 6.50 min, 100% B, 0.5 mL/min; 10.0 min, 0% B, 0.5
mL/min; Injection Volume: 100 uL; Column: Zorbax 300SB-C8
50.times.4.6 mm, 3.5 micron) was used to quantify tetanus toxoid in
the HPLC sample solution.
[0059] Non-adjuvanted tetanus toxoid (TT) vaccine (Aventis) was
calibrated against a lyophilized TT primary standard (List
Biologics) and used as a working standard. The working standard was
used to obtain a calibration curve from approximately 1 ug-TT/mL to
28 ug-TT/mL. The correlation coefficient for the linear regression
of the calibration curve was typically greater than 0.999. Tetanus
toxoid content results are the average of between 6 and 10
replicates.
Testing Procedure for Tetanus Toxoid Tip-Content
[0060] Tetanus toxoid content on the tips of the microneedles was
measured by fixing the toxoid in place on the substrate and lower
portions of the microneedles so that it could not be extracted into
the HPLC sample solution. A microneedle array was placed on a flat
surface with the needles pointing upward and 10 .mu.L of an
oil-based polyurethane coating solution (MINWAX Fast-Drying
Polyurethane) was applied to the array and allowed to coat the
substrate of the array. The polyurethane was allowed to cure for at
least 3 hours at ambient conditions. The array was subsequently
extracted and analyzed as described in the total content
method.
Aluminum Content by Inductively Coupled Plasma (ICP)
[0061] A 0.5 mL aliquot of the HPLC sample solution (described
above) was diluted to 5.0 mL with 4% nitric acid for analysis of
aluminum by ICP. The analysis was calibrated by using aluminum
standards at 1, 2, 4, 5, 6, 8 and 11 .mu.g/mL. The correlation
coefficient for the linear regression of the calibration curve was
typically greater than 0.999.
Enzyme-Linked Immunosorbant Assay (ELISA)
[0062] Quantitative determination of anti-tetanus toxoid IgG from
rabbit serum was performed by ELISA. Tetanus toxoid is coated on
the solid phase and binds anti-tetanus toxoid IgG from rabbit serum
samples. Plates are washed and bound rabbit IgG is detected with an
anti-rabbit IgG-HRP conjugate. The assay was standardized against
the EP veterinary standard rabbit anti-tetanus toxoid BRP Batch 1
(EDQM-European Pharmacopoeia Commission catalog number C2425600).
1000 arbitrary units (AU) from this ELISA is equivalent to 1
international unit (IU). Unless otherwise noted, anti-tetanus
toxoid IgG results are reported as the geometric average of 5
replicates.
Preparation of Microneedle Arrays
[0063] Microneedle arrays were prepared as follows. A circular disk
(area 2 cm.sup.2, thickness 1.02 mm) that was partially patterned
with an array of microneedles (37.times.37) in a square shape (1
cm.sup.2) centered on one side of the disk was prepared. The
needles were regularly spaced with a distance of 275 microns
between the tips of adjacent needles in a square-shaped pattern.
Individual needles were pyramidal in shape with a height of 250
microns and a square base having a side-length of 83.3 microns. The
tips were truncated with a flat, square-shaped top having a
side-length of 5 microns. Arrays were injection molded according to
the general description provided in International Patent
Application Publication No. WO 05/82596 and made from polycarbonate
(LEXAN HPS1R-1125, GE Plastics, Pittsfield, Mass.). The center of
the disk was then die cut to provide a microneedle array (area=1
cm.sup.2) having microneedles on approximately 90% of the surface
of the patterned side of the disk. The microneedle array had
approximately 1200 microneedles.
EXAMPLES
[0064] Additional features of the embodiments of the invention are
illustrated in the following non-limiting Examples.
Example 1
[0065] A polyvinylpyrrolidone (PVP) stock solution was prepared by
adding 825 mg PVP (PLASDONE K-29/32, Povidone USP, ISP
Technologies, Wayne, N.J.) to 25 mL water and mixing until the PVP
was dissolved. A stock solution was prepared by adding 50 mg
polysorbate 80 (TWEEN-80, Sigma Chemical Co., St. Louis, Mo.) to 25
mL ethanol. A diluted stock solution was prepared by adding 2 mL of
the polysorbate stock solution to 18 mL ethanol. A PVP priming
solution was prepared by adding 1 mL of the PVP stock solution to 9
mL of the diluted polysorbate stock solution. A microneedle array
was placed on a flat surface with the needles pointing upward and
an aliquot of 30 .mu.L of the PVP priming solution was applied to
the center of the array using a pipette and allowed to spread
across the array. The PVP priming solution was allowed to dry at
ambient conditions.
[0066] TWEEN-80 (90 mg) was added to water (30 mL) to prepare a
TWEEN-80 stock solution with a concentration of 3 mg/mL. PVP (1.8
g) was added to water (20 mL) to prepare a PVP stock solution with
a concentration of 90 mg/mL. Sucrose (1.8 g) was added to water (20
mL) to prepare a sucrose stock solution with a concentration of 90
mg/mL. Potassium citrate (1.8 g) was added to water (20 mL) to
prepare a potassium citrate stock solution with a concentration of
90 mg/mL. An antigen coating formulation was prepared by mixing
tetanus toxoid (Statens Serum Institute Lot 92-1, 888 Lf/mL) with
aliquots of the TWEEN-80, PVP, sucrose and potassium citrate stock
solutions.
[0067] An aliquot (15 .mu.L) of masking fluid (FC-43 FLUORINERT
Electronic Liquid) was applied to the center of the array using a
pipette and allowed to spread across the array. A 10 .mu.L aliquot
of the antigen coating formulation was applied to the center of the
masking fluid on the array using a pipette. The nominal amount of
tetanus toxoid in the applied antigen coating formulation was 10
.mu.g. The nominal amount of TWEEN-80 in the applied antigen
coating formulation was 6 .mu.g. The nominal amounts of PVP,
sucrose, and potassium citrate were 100 .mu.g. The antigen coating
formulation and masking fluid were allowed to dry at ambient
conditions for approximately 30 minutes to provide a dried antigen
coating on the array. Tetanus toxoid total-array content as
measured by reversed phase HPLC was 11.9 .mu.g (st. dev.=0.5
.mu.g). Tetanus toxoid tip-content was measured as 5.0 .mu.g (st.
dev.=1.2 .mu.g).
Examples 2-5
[0068] Coated arrays were prepared according to the procedure
described in Example 1 with the exception that the nominal amounts
of PVP, sucrose and potassium citrate were varied, as shown in
Table 1. Tetanus toxoid content of the coated array as measured by
reversed phase HPLC and tetanus toxoid content on the tips of the
microneedles was measured. The results are shown in Table 1.
TABLE-US-00001 TABLE 1 Tetanus toxoid content Potassium
Total-array, Tip-content, Ex. PVP Sucrose citrate Mean(st. dev)
Mean(st. dev) No. [.mu.g] [.mu.g] [.mu.g] [.mu.g] [.mu.g] 1 100 100
100 11.9 (0.5) 5.0 (1.2) 2 100 100 10 13.1 (0.4) 8.5 (0.5) 3 10 10
100 11.6 (0.8) 9.3 (1.3) 4 10 100 10 11.5 (0.3) 9.1 (1.4) 5 100 10
10 12.3 (0.3) 6.9 (0.7)
In Vivo Tetanus Toxoid Deposition
[0069] Microneedle devices were prepared by adhering antigen coated
arrays as described in Examples 1 to 5 to an adhesive backing. The
arrays were applied to hairless guinea pigs using an applicator as
generally described in U.S. Patent Application Ser. No. 60/578,651,
the disclosure of which is hereby incorporated by reference. The
applicator piston mass was 5.08 g and the devices were applied at a
velocity of 8.07 meters/second. The devices were applied to sites
on the soft tissue of the abdomen and muscle on the lower back
below the ribs and just above the pelvis. The application sites
were cleaned with 70% isopropyl alcohol and allowed to air dry for
at least 30 seconds prior to device application. Devices (N=5) were
removed at specified time points and the tetanus toxoid content
remaining on the arrays was measured by HPLC. The results are
summarized in Table 2.
TABLE-US-00002 TABLE 2 tetanus toxoid content [.mu.g] Array T = 0 T
= 1 T = 5 T = 10 T = 20 Example No. min min min min min 1 11.9 9.8
10.3 8.6 8.1 2 13.1 10.9 10.1 8.2 8.1 3 11.6 9.1 8.1 7.6 6.3 4 11.5
9.9 8.6 8.2 7.0 5 12.3 11.1 9.8 10.0 8.5
Example 6
[0070] A polyvinyl alcohol priming solution was prepared as
follows. An amount (250 mg) of polyvinyl alcohol (80% hydrolyzed,
typical Mw=9,000-10,000, CAS 9002-89-5, Aldrich, St. Louis, Mo.)
was added to water (25 mL) to prepare a polyvinyl alcohol stock
solution. An aliquot of polyvinyl alcohol stock solution (2 mL) was
added to ethanol (18 mL) to prepare a polyvinyl alcohol priming
solution. A microneedle array was placed on a flat surface with the
needles pointing upward and an aliquot of 30 .mu.L of the polyvinyl
alcohol priming solution was applied to the center of the array
using a pipette and allowed to spread across the array. The
polyvinyl alcohol priming solution was allowed to dry at ambient
conditions. An aliquot (15 .mu.L) of masking fluid (FC-43
FLUORINERT Electronic Liquid) was then applied to the center of the
array using a pipette and allowed to spread across the array. A 10
.mu.L aliquot of the antigen coating formulation was applied to the
center of the masking fluid on the array using a pipette. Antigen
coating formulations were prepared according to the general
procedure described in Example 1. The nominal amount of tetanus
toxoid in the applied antigen coating formulation was 10 .mu.g. The
nominal amount of TWEEN-80 in the applied antigen coating
formulation was 6 .mu.g. The nominal amounts of PVP, sucrose, and
potassium citrate were 100 .mu.g. The antigen coating formulation
and masking fluid were allowed to dry at ambient conditions for
approximately 30 minutes to provide a dried antigen coating on the
array. Tetanus toxoid total-array content as measured by reversed
phase HPLC was 10.4 .mu.g (st. dev.=0.7 .mu.g). Tetanus toxoid
tip-content was measured as 9.3 .mu.g (st. dev.=0.4 .mu.g).
Examples 7-14
[0071] Coated arrays were prepared according to the procedure
described in Example 6 with the exception that the nominal amounts
of PVP, sucrose and potassium citrate were varied, as shown in
Table 3. Tetanus toxoid content of the coated array as measured by
reversed phase HPLC and tetanus toxoid content on the tips of the
microneedles was measured. The results are shown in Table 3.
TABLE-US-00003 TABLE 3 Tetanus toxoid content Potassium
Total-array, Tip-content, Ex. PVP Sucrose citrate Mean (st. dev)
Mean (st. dev) No. [.mu.g] [.mu.g] [.mu.g] [.mu.g] [.mu.g] 6 100
100 100 10.4 (0.7) 9.3 (0.4) 7 100 100 10 10.4 (0.3) 8.2 (0.8) 8
100 10 100 10.2 (0.6) 9.1 (0.3) 9 10 100 100 9.5 (0.9) 6.7 (1.0) 10
10 10 100 9.3 (0.4) 5.8 (1.1) 11 10 100 10 9.5 (0.5) 6.9 (0.9) 12
100 10 10 10.2 (0.4) 5.6 (1.4) 13 10 10 10 7.9 (0.2) 4.5 (0.7) 14
55 55 55 10.6 (0.4) 8.4 (0.5)
Example 15
[0072] A coated array was prepared according to the procedure
described in Example 7. Tetanus toxoid total-array content as
measured by reversed phase HPLC was 10.7 .mu.g (st. dev.=0.9
.mu.g). Tetanus toxoid tip-content was measured as 8.7 .mu.g (st.
dev.=0.6 .mu.g). Arrays were applied to hairless guinea pigs as
described above in the section "in vivo tetanus toxoid deposition".
The amount of tetanus toxoid remaining on the array after removal
from the hairless guinea pig was measured by HPLC. The results are
summarized in Table 4.
Example 16
[0073] A coated array was prepared according to the procedure
described in Example 8. Tetanus toxoid total-array content as
measured by reversed phase HPLC was 11.4 .mu.g (st. dev.=0.3
.mu.g). Tetanus toxoid tip-content was measured as 8.6 .mu.g (st.
dev.=0.5 .mu.g). Arrays were applied to hairless guinea pigs as
described above in the section "in vivo tetanus toxoid deposition".
The amount of tetanus toxoid remaining on the array after removal
from the hairless guinea pig was measured by HPLC. The results are
summarized in Table 4.
Example 17
[0074] A coated array was prepared according to the procedure
described in Example 9. Tetanus toxoid total-array content as
measured by reversed phase HPLC was 10.8 .mu.g (st. dev.=0.3
.mu.g). Tetanus toxoid tip-content was measured as 6.8 .mu.g (st.
dev.=0.9 .mu.g). Arrays were applied to hairless guinea pigs as
described above in the section "in vivo tetanus toxoid deposition".
The amount of tetanus toxoid remaining on the array after removal
from the hairless guinea pig was measured by HPLC. The results are
summarized in Table 4.
Example 18
[0075] A coated array was prepared according to the procedure
described in Example 13. Tetanus toxoid total-array content as
measured by reversed phase HPLC was 11.7 .mu.g (st. dev.=0.3
.mu.g). Tetanus toxoid tip-content was measured as 5.3 .mu.g (st.
dev.=1.0 .mu.g). Arrays were applied to hairless guinea pigs as
described above in the section "in vivo tetanus toxoid deposition".
The amount of tetanus toxoid remaining on the array after removal
from the hairless guinea pig was measured by HPLC. The results are
summarized in Table 4.
TABLE-US-00004 TABLE 4 tetanus toxoid content [.mu.g] Array T = 0 T
= 1 T = 5 T = 10 T = 20 Example No. min min min min min 15 10.7
10.6 8.8 7.8 6.3 16 11.4 10.2 8.4 8.1 7.3 17 10.8 9.3 9.2 8.4 7.5
18 11.7 9.7 9.7 8.3 7.9
Example 19
[0076] Microneedle arrays were prepared as described above and
treated as follows. The arrays were plasma treated using a
Plasma-Therm VII 7000 series plasma processing system. A
diamond-like glass thin film was formed through plasma deposition
by feeding a mixture of tetramethyl silane (150 standard cubic
centimeter per minute, sccm) and oxygen (200 sccm) gas in an
unpressurized plasma with 2000 W RF power applied for 15 seconds.
The arrays were then subsequently treated with an oxygen plasma
(400 sccm) under a pressure of 150 mTorr with 300 W power for 60
seconds to remove elemental and covalently bonded carbon from the
surface atomic layers and to make the surface hydrophilic.
[0077] An aliquot (15 .mu.L) of masking fluid (FC-43 FLUORINERT
Electronic Liquid) was applied to the center of the array using a
pipette and allowed to spread across the array. A 10 .mu.L aliquot
of the antigen coating formulation was applied to the center of the
masking fluid on the array using a pipette, Antigen coating
formulations were prepared according to the general procedure
described in Example 1. The nominal amount of tetanus toxoid in the
applied antigen coating formulation was 10 .mu.g. The nominal
amount of TWEEN-80 in the applied antigen coating formulation was 6
.mu.g. The nominal amounts of PVP, sucrose, and potassium citrate
were 100 .mu.g. The antigen coating formulation and masking fluid
were allowed to dry at ambient conditions for approximately 30
minutes to provide a dried antigen coating on the array. Tetanus
toxoid total-array content as measured by reversed phase HPLC was
12.1 .mu.g (st. dev.=0.6 .mu.g). Tetanus toxoid tip-content was
measured as 9.6 .mu.g (st. dev.=1.2 .mu.g). Arrays were applied to
hairless guinea pigs as described above in the section "in vivo
tetanus toxoid deposition". The amount of tetanus toxoid remaining
on the array after removal from the hairless guinea pig was
measured by HPLC. The results are summarized in Table 6.
Examples 22-23
[0078] Coated arrays were prepared according to the procedure
described in Example 19 with the exception that the nominal amounts
of PVP, sucrose and potassium citrate were varied, as shown in
Table 5. Tetanus toxoid content of the coated array as measured by
reversed phase HPLC and tetanus toxoid content on the tips of the
microneedles was measured. The results are shown in Table 5. Arrays
were applied to hairless guinea pigs as described above in the
section "in vivo tetanus toxoid deposition". The amount of tetanus
toxoid remaining on the array after removal from the hairless
guinea pig was measured by HPLC. The results are summarized in
Table 6.
TABLE-US-00005 TABLE 5 Tetanus toxoid content Potassium
Total-array, Tip-content, Ex. PVP Sucrose citrate Mean (st. dev)
Mean (st. dev) No. [.mu.g] [.mu.g] [.mu.g] [.mu.g] [.mu.g] 19 100
100 100 12.1 (0.6) 9.6 (1.2) 20 100 100 10 12.4 (0.4) 9.3 (1.7) 21
10 10 100 12.3 (0.4) 8.3 (0.8) 22 10 100 10 11.3 (0.4) 8.3 (1.3) 23
100 10 10 12.3 (0.3) 8.4 (2.0)
TABLE-US-00006 TABLE 6 tetanus toxoid content [.mu.g] Array T = 0 T
= 1 T = 5 T = 10 T = 20 Example No. min min min min min 19 12.1 9.6
9.7 8.0 8.4 20 12.4 10.5 9.8 8.4 7.9 21 12.3 10.7 10.4 10.1 10.2 22
11.3 8.4 9.1 8.3 7.6 23 12.3 10.4 9.5 7.7 8.2
[0079] Embodiments of the invention have been described in detail.
Those skilled in the art will appreciate that changes and
modifications may be made to the described embodiments without
departing from the true scope and spirit of the invention.
* * * * *